Experimental and kinetic investigation on soot formation in laminar diffusion flame of Jet A/butanol blends

Abstract

The effects of butanol blending to Jet A on soot formation characteristics are investigated on a laminar coflow liquid burner with a butanol volume ratio of 0–80 %. With the increase of the butanol blending ratio, the flame liftoff gradually increases, but the flame height and flame brightness gradually decrease. The laser-induced incandescence (LII) signal of soot develops from the two wings to the axis, meanwhile, the sooting area becomes smaller. The addition of butanol does not alter the distribution shape of polycyclic aromatic hydrocarbons (PAHs), which exhibit high concentrations on the wings and maintains the shape of a "hollow cone". With the increase in the butanol blending ratio, the LII-soot and LIF-PAH signals at different heights all decreased, and the peak and average signals of soot and PAH decreased nearly linearly. A new butanol-Jet A mechanism including PAH formation is established. The simulation results show that the formation of A1 mainly comes from propylbenzene (PBZ) in Jet A, and the degree of decreases of the maximum mole fraction of A4 is consistent with the decrease in the volume fraction of Jet A, suggesting that addition of butanol results in reduced content of Jet A and the dilution of PBZ reduces the formation of PAH, ultimately leading to the reduction of soot.